Welding rod



. Patented Feb. 21, 1933 'ourrrzo ,s'rA'r'ss j enonen '1'.

PATENT OFFICE SOU'I'HGATE, OF FOREST HILLS, NEW YORK, ASSIGNOB' TO UNION CARBIDE 86 CARBON RESEARCH LABS. INC A CORPORATION OF NEW YORK WELDING ROD No Drawing. I My invention relates to welding rods and especially to a coated welding rod adapted for use in arc welding. An ob ect of my m- I v vention isto devise a welding rod which shall have a coating that is conductive so that it will be unnecessary to remove the coating from a portion of the rod to enable contact to be made. Another' object of my invent on is to produce a'rod having a coating WhlCl'l 1 shall assist in the stabilization of the arc.

A further object of my invention is to prop duce a rod having a coating which shall" protect the deposited weld metal from excessive oxidation and from nitrification. These and other objects of my invention will be P evident from the following specification.

In carrying out one embodiment of my invention I coat a rod or wire, composed principally of iron,-with a mixture contammg 2 carbon, an alkali or an alkaline earth and a metal which forms an alloy'with iron. The' alkali or alkaline earth may bein'the form of an oxide vor may be in a salt. 'WllllG I have found calcium, barium, and strontium compounds, especially suitable .for thispur-- pose I prefer to use compounds of calcium .because of their cheapness. The ferro-alloyforming metal may be included in the coating as an oxide, or in the acid radical of a salt of the alkali metal or alkaline earth metal. Ihave found that chromium, tungsten, molybdenum, zirconium, titanium and cerium are well suited for this purpose because of theirdenitrifying properties. In

most cases I prefer to'use calcium chromate in the coating'by virtue of its relative cheapness. and readier availability. The carbon may be introduced into the coating'by using anor anic binder which is carbonized during ba ing. Another way of introducing the carbon is .to employ colloidal graphite in the v coating mix. The. carbon serves toincrease the conductivity, and also serves to reduce V the ferro-alloying metal. It is also'irequentv 1y desirable to include silica'for the purpose of assisting in forming a protective coating Qof slag. The constituents of the coating may be mixed with wateran'd'applied to the rods by dipping or brushing. If. the rods are to v be roughly handled it may be desirable to in-' Application filed February l0,v 1931. Serial No. 514,911.

clude a small amount of glue or other adhesivesubstance especially in cases where 001- loidal graphite is not used.

In preparing welding rods in accordance with my invention I prefer to use a coating made up in accordance with one of the following formulae:

CaO.CrO 4 to 5 parts; 0, 1' part; SiO 3 parts. I v

CtaQMoO 5 to 6 parts; C, 1 part; SiO 3 ar s.

CaO.WO 7 to 9 parts; C, 1 part; SiO 3 parts. i

CtaOTiO 4 to 5 parts; 0, 1 part; SiO 3 ar s.

CaQCeO 6 to 8 parts; C, 1 part; SiiO 3 parts. CaOZrO 5 to 6 parts; G, 1 part; SiO 3 parts.

The carbon ratio given above is that for free carbon. When an or anic binder is 'employed it should be used in such proportion that upon carbonization the above ratio holds. The proportion of silica may be varied within relatively wide limits.- However the use of three parts of silica in the above "stated formulae gives a satisfactory slag formation. Instead of calcium I may use other alkaline earths or even oxides, hydroxides or salts of alkali metals.

A rod prepared in accordance with my invention has numerous advantages among which may be mentioned the protection of the welding metal during depositionand cooling against attack ofoxygen, nitrogen 5 or other gases; the improvement in the qual-- ity of the deposited metal and of the surrounding body metal; the increase of penetration o'f'the'weld metal; and the fact that the coating is conductive thereby adapting the coated rod for use with automatic welding machines. These advantages are due in 1 part to the stability of the constituents at very high temperatures thus minimizing decomposition in advance of actual fusion. 5 Also the alkaline-earth metals employed have very high are stabilizing properties. Furthermore, the quantities of salts or oxides ofthe metals required are so low that the coating of slag is relatively thin. The other metals employed in the coating, such as chromium, are cleansing agents due to their power of combining with mtrogen, transferring it to the slag and preventing its combining with the deposited ferrous metal.

I claim:

1. A welding rod comprising a core redominantly of iron and an electrically conductive coating; thereon,comprising substantially one part 0 carbon,four to nine parts of acompound of an alkaline earth metal and a nitrogen-combining ferro-alloy-formin metal or equivalent mixture of oxides, an substantially 3 parts of a slag-forming material.

2. A welding rod comprising a core predominantly of iron and an electricall conductive coating thereon, comprising su stantially one part of carbon, parts of silica and from four to nine parts of an oxygen containin compound of an'alkaline earth metal and a nitrogen-combining ferro-alloy-forming metal or' equivalent mixture of oxides;

3. A welding rod comprising a core predominantly ofiron and an. electrically conductive coating thereon, said coating comprising substantially one part of graphite, from o taining compound of an alkaline earth 'metal and a nitrogen-combining ferro-alloy-forming metal or e and substantial material.

4. A weldin rod comprising a core pre dominantly 0; iron and a coating thereon comprising an oxygen-containing compound of an alkaline earth metal and a nitro encombining ferro-allo -forming metal, a s agforming material an carbon the carbon being present in an amount suflicient to reduce to the metallic state the second-named metal, and-the slag-forming material being present in an amount greater than the carbon and less than said oxygen-containing compound.

5. A weldin dominantly 0 iron and a coating thereon comprising carbon one part, com ounds of calcium and chromium substantia 1y 4 to 5 parts and silica substantially 3 parts.

6. A welding rod comprising a core predominantly of iron and a coating thereon comprising graphite one part, compounds of calcium and chromium substantia parts and silica substantially 3 parts.

7. A weldinfg rod comprising a'core predominantly 0 comprising calcium chromate substantially 4 to 5 parts, graphite one part and silica substantlally 3 parts. 1

8. A weldlng rod comprising a core predominantly of iron and a coating thereon y 3 parts of a slag-forming comprising carbon one art, oxygen-contaming compounds ofalka ine earth metal and titanium substantially 4 to 5 parts and silica substantiallv 3 Darts.

substantially three ui' to nine parts of an oxygen conuivalent mixture of oxides,-

iron and a coating thereon 9. A weldin rod as claimed in claim 8 in which the alka ine earth metal is calcium.

10. A welding rod comprising a core predominantly of Iron and a coating thereon,

.said coating com' rising an oxygen-containo tungsten and an alkaline 1 ing compound earth metal in equivalent molecular ,por-

:tions or equivalent mixtures of the oxides of rod consisting of a core pre- 

